Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic Vehicle

Abstract

The focus of this paper is on control design and simulation for an air-breathing hypersonic vehicle. The challenges for control design in this class of vehicles lie in the inherent coupling between the propulsion system, and the airframe dynamics, and the presence of strong flexibility effects. Working from a highly nonlinear, dynamically-coupled simulation model, control designs are presented for velocity, angle-of-attack, and altitude command input tracking for a linearized version of a generic air-breathing hypersonic vehicle model linearized about a specific trim condition. Control inputs for this study include elevator deflection, total temperature change across the combustor, and the diffuser area ratio. Two control design methods are presented, both using linear quadratic techniques with integral augmentation, and are implemented in tracking control studies. The first approach focuses on setpoint tracking control, whereas in the second, a regulator design approach is taken. Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

Control-Relevant Modeling, Analysis, and Design for Scramjet-Powered Hypersonic Vehicles

“…Moreover, all trim analysis has focused on level flight. Figure 3 shows the level-flight trimmable region for the nominal vehicle being considered 7,19,26,29,41 (using the original nominal engine parameters). We are interested in how the static and dynamic properties of the vehicle vary across this region.…”

“…across the combustor has been computed, it can be substituted into equation (26) and one can "try" to solve for M 3 . Since the left hand side of equation (26) lies between 0 (for M 3 = 0) and 0.2083 (for M 3 = 1), it follows that if the right hand side of equation (26) is above 0.2083 then no solution for M 3 exists.…”

“…Within this paper, we exploit the generic carrot-shaped vehicle 3DOF (plus flexibility) model presented in 7,19,26,29 . A myriad of issues exist that make control design for this hypersonic vehicle a potentially challenging problem:…”

“…The computational time associated with the enhanced model is significant, thus making it cumbersome for control-relevant analysis. The simple 1D Rayleigh flow engine model discussed within 7,19,26,29 will be used in the current paper.…”

“…In this paper, we consider a first principles nonlinear 3-DOF dynamical model for the longitudinal dynamics of a generic scramjet-powered hypersonic vehicle [7][8][9][19][20][21][22][23][24][25][26][27][28] . The vehicle is 100 ft long with weight (density) 6,154 lb per foot of depth and has a bending mode at about 22 rad/sec.…”